Drilling tool replacement apparatus

ABSTRACT

In accordance with the present invention, there is provided a drilling tool replacement apparatus, the apparatus comprising: a drilling tool holder adapted to receive one or more drilling tools; a drilling tool lifter adapted to move a drilling tool between a first position and an elevated orientation; and a transfer apparatus adapted to transfer a drilling tool from the drilling tool holder to the drilling tool lifter.

TECHNICAL FIELD

The present invention relates to a drilling tool replacement apparatus for loading a drilling tool onto a drill string. Additionally, the apparatus of the present invention allows for a drilling tool coupled to a drill string to be removed from the drill string. More specifically, the apparatus of the present invention allows for a drilling tool coupled to a drill string to be replaced with another drilling tool.

BACKGROUND ART

The following discussion of the background art is intended to facilitate an understanding of the present invention only. The discussion is not an acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the application.

Mobile drilling units are typically employed to drill holes for blasting in mining and quarrying operations. Such units commonly comprise a pivoting mast mounted on a drill platform. A drill string is mounted within or onto the mast to drill into the earth. The drill string comprises a drilling tool and series of drill rods. The drilling tool is mounted on the working end of the drill string and retains a drill bit that is driven into the earth. The drill rod connects the drilling tool to a drill rotation source mounted on the mast. Drilling fluid and rotational torque are provided through the drill rod to the drilling tool to allow drilling operation to commence. As the drilling operation continues, additional lengths of drill rod are added to the drill string.

Before drilling can commence, the drilling tool will need to be coupled to the drill string. This process involves the manual positioning of the drilling tool beneath a drill rod to permit the coupling. At the completion of a drilling operation, the drilling tool will need to be uncoupled from the drill rod and be removed from the drill string. Whilst many parts of drilling operations may be completed autonomously, the coupling/decoupling of drilling tools still requires manual intervention from an operator. This presents a significant danger to operators and injuries can occur as a result of uncontrolled movement of the drilling tools during the changeover process. The risks increase even further with large diameter drilling operations where the drilling tools are much larger and heavier.

Throughout this specification, unless the context requires otherwise, the word “comprise” or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

SUMMARY OF INVENTION

In accordance with the present invention, there is provided a drilling tool replacement apparatus, the apparatus comprising:

-   -   a drilling tool holder adapted to receive one or more drilling         tools;     -   a drilling tool lifter adapted to move a drilling tool between a         first position and an elevated orientation; and     -   a transfer apparatus adapted to transfer a drilling tool from         the drilling tool holder to the drilling tool lifter.

In one form of the present invention, the drilling tool handling apparatus is mounted to a drill platform of a mobile drill unit.

In one form of the present invention, the drilling tool replacement apparatus is adapted to position a drilling tool beneath a drill rod coupled to a drill rotation source to permit the coupling/decoupling of the drilling tool and the drill rod. Additionally or alternatively, the drilling tool replacement apparatus is adapted to position a drilling tool that is coupled to a drill rod beneath the drill rotation source to permit the coupling/decoupling of the drill rod and the drill rotation source.

In one form of the present invention, the first position is less than 30° to the horizontal plane. In one form of the present invention, the first position is less than 25° to the horizontal plane. In one form of the present invention, the first position is less than 20° to the horizontal plane. In one form of the present invention, the first position is less than 15° to the horizontal plane. In one form of the present invention, the first position is less than 10° to the horizontal plane. In one form of the present invention, the first position is less than 5° to the horizontal plane. Preferably, the first position is substantially in the horizontal plane. Where the drilling tool handling apparatus is mounted to a drill platform of a mobile drill unit, the first position is substantially parallel to the drill platform.

Preferably, the first position is substantially horizontal to the drilling platform.

As discussed above, the drilling tool lifter is adapted to move a drilling tool between a first position and an elevated orientation. Throughout this specification, unless the context requires otherwise, the term “elevated orientation”, will be understood to refer to any orientation where the angle between the longitudinal axis of the drilling tool and the first position is greater than 0°. Where the drilling tool handling apparatus is mounted to a drill platform of a mobile drill unit, the elevated orientation will be understood to refer to any orientation where the angle between the longitudinal axis of the drilling tool and the drill platform is greater than 0°.

Preferably, the elevated position is substantially parallel to the drill mast. As would be appreciated by a person skilled in the art, drill rigs typically operate in a wide range of drill angles, the drilling tool handling apparatus of the present invention is adapted to lift a drilling tool to a position substantially parallel to the drill mast to facilitate the coupling of the drilling tool to the drill string. Furthermore, the drilling tool lifter may be moved into a position substantially parallel to the drill mast to facilitate the decoupling of a drilling tool from a drill string.

In one form of the present invention, the drilling tool holder is adapted to receive the one or more drilling tools in an orientation that is less than 30° to the horizontal plane. In one form of the present invention, the drilling tool holder is adapted to receive the one or more drilling tools in an orientation that is less than 25° to the horizontal plane. In one form of the present invention, the drilling tool holder is adapted to receive the one or more drilling tools in an orientation that is less than 20° to the horizontal plane. In one form of the present invention, the drilling tool holder is adapted to receive the one or more drilling tools in an orientation that is less than 15° to the horizontal plane. In one form of the present invention, the drilling tool holder is adapted to receive the one or more drilling tools in an orientation that is less than 10° to the horizontal plane. In one form of the present invention, the drilling tool holder is adapted to receive the one or more drilling tools in an orientation that is less than 5° to the horizontal plane. Preferably, the drilling tool holder is adapted to receive the one or more drilling tools in a substantially horizontal orientation. Throughout this specification, unless the context requires otherwise, the term “horizontal orientation”, will be understood to refer to an orientation where the longitudinal axis of the drilling tool is substantially parallel to the horizontal plane. Where the drilling tool handling apparatus is mounted to a drill platform of a mobile drill unit, the drilling tool holder is adapted to receive drilling tools such that the longitudinal axis of the received drilling tool is substantially parallel to the drill platform. Preferably, the one or more drilling tools are received substantially horizontally in the drilling tool holder. Preferably, the one or more drilling tools are stored substantially horizontally in the drilling tool holder. Still preferably, the one or more drilling tools are releasably retained within the drilling tool holder.

In one form of the present invention, the drilling tool holder is provided with one of more drilling tool compartments. Preferably, where there are two or more drilling tool compartments, the drilling tool compartments are provided in a parallel array.

In one form of the present invention, each drilling tool compartment is adapted to receive a drilling tool therein. Alternatively, each drilling tool compartment is adapted to receive a drilling tool thereon.

Preferably, the drilling tool lifter comprises a drilling tool retaining portion adapted to receive a drilling tool. More preferably, the drilling tool retaining portion releasably retains a drilling tool. Still preferably, the drilling tool retaining portion is provided with a clamping means, for example, clamps that engage to retain the drilling tool in the drilling tool retaining portion.

In one form of the present invention, the drilling tool lifter comprises a lifting arm coupled to the drilling tool retaining portion. Preferably, the lifting arm is adapted to move the drilling tool retaining portion between a horizontal position and an elevated orientation.

In one form of the present invention, the drilling tool retaining portion has a lower end and an upper end. In one embodiment, the lower end is mounted to the drill platform. Preferably, the lower end is in hingedly engaged with the drill platform.

In one form of the present invention, the drilling tool lifter further comprises a locating arrangement. Preferably, the locating arrangement is adapted to engage with the drilling tool to assist in the retention of the drilling tool in the drilling tool lifter. In a preferred form of the present invention, the locating arrangement comprises a locating bucket. Preferably, the locating bucket is adapted to receive and retain the drilling tool. More preferably, the locating bucket is positioned at the lower end of the drilling tool lifter. Still preferably, the locating bucket is in communication with the drilling tool retaining portion.

In one form of the present invention, the drilling tool replacement apparatus further comprises a rod locating arrangement adapter. It is envisaged that the drilling tool lifter may also be used to add drill rods to the drill string once drilling has commenced. Such configurations include those disclosed in the Applicants co-pending provisional application AU2018900521, the disclosure of which is incorporated herein in its entirety. When used for adding drill rods to a drill string, it is envisaged that the drilling tool lifter may include a rod locating arrangement that is adapted to engage and retain with the drill rod. The rod locating arrangement adapter of the present invention is adapted to engage with such a rod locating arrangement to enable the engagement of the drilling tool with such rod locating arrangement. Preferably, the rod locating arrangement adapter is a rod pin adapter. In this embodiment, the rod locating arrangement includes a rod locating pin at the lower end of the rod lifter. During operation, drill rods will be guided onto the rod locating pin. In this embodiment, the rod pin adapter comprises a female receptacle and a bucket portion. It is envisaged that the bucket portion will be suitable for use as the locating bucket of the drilling tool lifter. The female receptacle of rod pin adapter is intended to slide onto the rod locating pin, thereby enabling the use of the bucket portion as the locating bucket.

In one form of the present invention, the drilling tool lifter is adapted to further receive a drill rod. Preferably, the drilling tool retaining portion is adapted to receive the drill rod. More preferably, the drilling tool retaining portion receives and positions the drill rod directly behind the drilling tool. As identified by the inventors, the positioning of the drill rod behind the drilling tool permits the drilling tool to be coupled to the drill rod and decoupled from the drill rod. In one embodiment, the drill rod and the drilling tool are coupled at a screw type joint.

In one form of the present invention, the drilling tool lifter further comprises one or more rod rotators. Preferably, the one or more rod rotators facilitate the coupling/decoupling of a drill rod to a drilling tool. More preferably, the one or more rod rotators are adapted to rotate a drill rod relative to the drilling tool to permit the coupling/decoupling of the drill rod to the drilling tool. Still preferably, each rod rotator comprises one or two rotating drums which engage with a drill rod to rotate the drill rod.

In an alternative form of the present invention, the drilling tool lifter is adapted to further receive a drilling tool that has been coupled to a drill rod. It is envisaged that in this form of the present invention, the drilling tool and the drill rod may be coupled prior to being positioned in the drilling tool lifter. Furthermore, the coupled drilling tool and drill rod may be stored in the drilling tool holder.

In one form of the present invention, the transfer apparatus is adapted to releasably engage with a drilling tool. Preferably, the transfer apparatus is adapted to lift a drilling tool out of the drilling tool holder. More preferably, the transfer apparatus engages and lifts a drilling tool in a substantially horizontal orientation. Still preferably, once the drilling tool is lifted out of the drilling tool holder, the transfer apparatus is adapted to position the drill tool above the drilling tool retaining portion. Once positioned above the transfer apparatus may lower the drilling tool into the drilling tool retaining portion and disengage with the drilling tool.

In one form of the present invention, the transfer apparatus is adapter to transfer a drill rod from the drilling tool holder to the drilling tool lifter for coupling to the drilling tool.

In one form of the present invention, the transfer apparatus is provided with one or more engagement means adapted to couple with the drilling tool. Preferably, each engagement means comprises a drilling tool lifting arm.

Preferably, the transfer apparatus further comprises a track positioned between the drilling tool holder and the drilling tool lifter. More preferably, the engagement means is adapted to engage with the track. Still preferably, the arrangement of engagement means with the track allows for the engagement means to be positioned along the track.

In one form of the present invention, where a rod locating arrangement adapter is required, the rod pin adapter is stored in the drilling tool holder. Preferably, the transfer apparatus is adapted to engage with the rod pin adapter to move it from the drilling tool holder to the drilling tool lifter for positioning over the rod locating pin.

Preferably, the drilling tool lifter will lift the distal end of the drilling tool towards the drill mast of the drilling unit. Preferably, the drilling tool lifter will substantially align the drilling tool with the drill mast. It is envisaged that the alignment of the drilling tool with the drill mast will facilitate the coupling of the drilling tool to the drill string.

In one form of the present invention, where the drilling tool is coupled to a drill rod, the drilling tool lifter will lift the distal end of the drill rod towards the drill mast of the drilling unit. Preferably, the drilling tool lifter will substantially align the drilling tool and drilling rod with the drill mast. It is envisaged that the alignment of the drilling tool with the drill mast will facilitate the coupling of the drill rod to the drill rotation source.

In one form of the present invention, where two or more drilling tool compartments are provided in the drilling tool holder, the drilling tool lifter may engage with drilling tools in either compartment. Preferably, different types of drilling tools are provided in separate compartments. It is envisaged that by providing different drilling tools that the drilling tool replacement apparatus may be used to replace one type of drilling tool on a drill string with another type of drilling tool. Suitable drilling tools may be selected from rotary drilling tools and down-the-hole hammer drilling tools. Alternatively, the drilling tool replacement apparatus may be used to replace a drilling tool on a drill string with another drilling tool of the same type. It is envisaged that the drilling tool holder may be loaded with multiple drilling tools of the same type that will be available for selection by the drilling tool replacement apparatus. In the event of a drilling tool malfunction or drill bit wear, the drilling tool can then be easily replaced with another drilling tool stored in the drilling tool holder.

Preferably the drill rotation source is mounted on the exterior of the drill mast. More preferably, the drill mast is solid. Where the drill rotation source is mounted on the exterior of the drill mast, the drilling tool lifter is preferably adapted to position the rod beneath the drill rotation source to facilitate attachment.

In one form of the present invention, the replacement of the drilling tool by the drilling tool replacement apparatus is fully automatic. Preferably, the replacement of the drilling tool by the drilling tool replacement apparatus can be completed autonomously.

In accordance with a further aspect of the present invention, there is provided a method of drilling, the method comprises operation of a drilling unit having a drilling tool replacement apparatus as described above mounted thereon for the addition and/or removal of drilling tools.

In accordance with a further aspect of the present invention, there is provided a method of replacing a drilling tool, the method comprises the use of a drilling tool replacement apparatus as described above to replace the drilling tool.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features of the present invention are more fully described in the following description of several non-limiting embodiments thereof. This description is included solely for the purposes of exemplifying the present invention. It should not be understood as a restriction on the broad summary, disclosure or description of the invention as set out above. The description will be made with reference to the accompanying drawings in which:

FIG. 1 is a side elevation of the drilling tool replacement apparatus of the present invention;

FIG. 2 is a plan view of the drilling tool replacement apparatus of the present invention;

FIG. 3 is a front elevation of the drilling tool holder;

FIG. 4 is a side elevation of the drilling tool lifter of the present invention during elevation;

FIG. 5 is a side elevation of the transfer apparatus of the present invention;

FIG. 6 is a side elevation of the rod pin adapter; and

FIG. 7 is side elevation of two drilling tools.

DESCRIPTION OF EMBODIMENTS

In FIGS. 1-7, there is shown a drilling tool replacement apparatus 10 in accordance with the present invention. The drilling tool replacement apparatus 10 is primary adapted for use on a drilling unit 12.

In FIGS. 1-2 there is shown the drilling tool replacement apparatus 10 as mounted on a drilling unit 12. In the embodiment shown in FIGS. 1-2 the drilling tool replacement apparatus 10 is mounted on a drill platform 14. The drill platform 14 is supported on a crawler undercarriage 16 that allows the drill platform 14 to be positioned relative to the area to be drilled. The drill platform 14 further comprises levelling jacks 18 that may be positioned to provide stability when drilling.

The mobile drilling unit 12 includes drill mast 20 which is hinged to the drill platform 14, such that the drill mast 20 is able to tilt relative to the drill platform 14. The drill mast 20 is able to move between a horizontal position and an elevated position for drilling at varying angles. The horizontal position allows for the transport of the drill platform 14. Hydraulic cylinders (not shown) control the movement of the drill mast 20.

The drilling unit 12 further comprises an operator cab 22 which houses the operating controls for the drilling operation, together with monitoring instruments. Whilst the embodiment shown in FIGS. 1-2 comprises an operator cab, it is envisaged that operation of the drilling unit 12 may be controlled autonomously. Where drilling is completed by autonomous drilling methods, it is envisaged that the operator cab 22 may be used as a control room for remote signalled drilling operations, along with monitoring instruments.

The drilling unit 12 comprises a drill rotation source 24 supported on the drill mast 20. The drill rotation source 24 is guided for longitudinal movement along the drill mast 20. Movement of the drill rotation source 24 is typically controlled by a hoist (not shown). Hydraulic head actuators (not shown) control the movement of the drill rotation source 24 and the hoist. Whilst the drill rotation source 24 shown in the Figures is adapted move along the drill mast 20, it is envisaged that other rotation drive mechanisms may be employed, such as for example a Table Drive. As would be understood by a person skilled in the art, where a Table Drive is utilised, it does not move along the drill mast 20.

The drilling unit 12 further comprises a hydraulic pump mechanism (not shown) adapted to supply hydraulic fluid for hydraulic operations. The hydraulic pump mechanism is operated by a diesel engine (not shown) mounted on the drill platform 14.

The drilling tool replacement apparatus 10 of the present invention is adapted to add and remove drilling tools 26 from a drill string. As would be appreciated by a person skilled in the art and with reference to FIG. 7, a drilling tool 26 is a piece of drilling equipment that retains a drill bit 28 and permits operation of the drill bit 28. The drilling tool 26 is coupled to a drill rod 30 which is in turn coupled to the drill rotation source 24. The coupling of the drill rod 30 to the drill rotation source 24 permits rotational forces and drilling fluid to travel to the drilling tool 26 by way of the drill rod 30. The drill rotation source 24 is moved down the drill mast 20 to force the drill bit 28 of the drilling tool 26 into the earth. As drilling progresses, additional drill rods 30 are added to the drill string.

As would be appreciated by a person skilled in the art, there are different types of drilling tools 26 that may be used. Common types of drilling tools 26 include rotary drilling (RD) tools, percussion assisted rotary drilling (PARD) tools or a down the hole hammer (DTHH) tools. As would be appreciated by a person skilled in the art, each of these drilling tools 26 operates in a different manner.

Typical RD tools employ a rotational drill bit 28 at the end of the drill rod to cut or crush/grind into the formation. Both rotational forces and downward pressure must be exerted on the drill bit 28 to drive it through the formation. The rotation is exerted on the drill bit 28 by the drill rotation source 24. The downward pressure is exerted on the drill bit by longitudinal movement along the drill mast. As the drilling continues, a fluid stream such as compressed air or a liquid is sent down the drill rod to flush and clear the cuttings from within the borehole.

Typical DTHH tools include a hammer assembly within the DTHH tool at the end of the drill rod. The hammer assembly comprises a pneumatic or hydraulic percussion mechanism, commonly called the hammer, which is located directly behind a drill bit 28. The pneumatic or other fluid (hydraulic) percussion mechanism strikes the impact surface of the bit directly to drive the drill bit 28 into the rock, chipping away rock as it is rotated and downward pressure is applied to the hammer assembly thereby producing a hole. Compressed air or another fluid is provided down the drill rod to actuate the pneumatic hammer and to flush out the broken rock cuttings. The drill rod transmits the necessary feed force and rotation to the hammer assembly.

Typical PARD tools use both rotary and low(er) percussive action in order to chip away rock and produce a hole. The combination of rotation and percussion helps the drill achieve a cutting/crushing and grinding (rotary) action at the same time as a chipping (percussive) action. Usually these motions are hydraulically or pneumatically driven. A hole is formed when the power source is transmitted through the drill rod to the drill bit 28.

As would be appreciated by a person skilled in the art, different drilling tools 26 may be selected depending on the hardness of the rock that is being drilled. Rotary tools generally have a high penetration rate and are more economic for drilling in soft rocks. However, the use of rotary tools in hard rock requires a drilling rig with high pull down force and rotation force capacities to drive the bit through the rock. This presents a significant capital expenditure for the high capacity drill rig itself, along with higher operating costs to power the large volume compressors used in rotary drilling. Furthermore, the rotary drill bits 28 may wear at a quicker rate in hard rock, requiring ongoing replacement costs. These factors together contribute to a much higher cost impediment to such operations. Unlike RD tools, DTHH tools are generally more suited and more economic for drilling of hard rock material. Accordingly, it is generally more economical to use DTHH tools in hard rock. The difference in economy typically increases when drilling larger diameter holes (+127 mm).

The drilling tool replacement apparatus 20 of the present invention is envisaged to permit the loading of a drilling tool 30 onto a drill string and the subsequent removal of the drilling tool 30 from the drill string. It is further envisaged that the drilling tool replacement apparatus 20 will permit the replacement of one type of drilling tool 26 from a drill string with another type of drilling tool 26 without the need for manual handling of the drilling tools 26 by an operator. This allows the drilling tool 26 assembly to be replaced when rocks of different hardness are encountered during drilling.

The drilling tool replacement apparatus 10 comprises a drilling tool holder 32 which is adapted to receive one or more drilling tools 26. As best seen in FIGS. 2-3, the drilling tool holder 32 comprises one or more drilling tool compartments 34. The drilling tool compartments 34 are arranged along the drill platform 14 such that the drilling tools 26 lay substantially horizontally along the drill platform 14 when stored in the drilling tool holder 32. When multiple drilling tool compartments 34 are used, these drilling tool compartments 34 are arranged parallel to one another. It is envisaged that each drilling tool compartment may store more than one drilling tool 26.

The drilling tool replacement apparatus 10 comprises a drilling tool lifter 36. In the embodiment shown in FIGS. 1-2, the drilling tool lifter 36 is mounted to the drill platform 14 adjacent to the drilling tool holder 32. The drilling tool lifter 36 has a lower end 38 which is position proximate to the drill mast 20 and an upper end 40 at the distal to the lower end 38. As best seen in FIG. 2, the drilling tool lifter 36 is arranged parallel to the direction of the drilling tools 26 in the drilling tool holder 32. As best seen in FIG. 4, the drilling tool lifter 36 comprises a drilling tool retaining portion 42 adapted to receive a drilling tool 26. In the embodiment shown in the Figures, the drilling tool retaining portion 42 is provided in the form of a “U” shaped section that is sized to receive the drilling tool 26. The drilling tool lifter 36 also comprises a lifting arm 44 coupled to the drilling tool retaining portion 42. In the embodiment shown in FIG. 4, the lifting arm 44 is hydraulically actuated (not visible). The lifting arm 44 actuates to adjust the drilling tool retaining portion 42 from a first position, for example a horizontal orientation towards an elevated orientation that is substantially parallel to the drill mast 20. The lifting arm 44 functions to properly position the drilling tool retaining portion 42 whether the drill mast 20 is vertical or at an angle from vertical. When a drilling tool 26 is retained within the drilling tool retaining portion 42, the drilling tool lifter 36 will adjust the drilling tool 26 from a horizontal orientation to an elevated orientation. In order to facilitate this movement, the lower end 38 of the drilling tool retaining portion 42 is hingedly attached to the drill platform 14, allowing the lifting arm 44 to pivot the drilling tool retaining portion 42 about the hinge. Alternative lifting means may be used to position the drilling tool retaining portion 42. For example a screw feed type system may be implemented.

At the lower end of the drilling tool retaining portion 42 there is provided a locating arrangement, for example a locating bucket 46. As best seen in FIG. 4, the locating bucket 46 extends from the lower end 38 towards the upper end 40. The locating bucket 46 is sized such that the lower end of the drilling tool 26 may be received therein. Once the drilling tool 26 has engaged with the locating bucket 46, the locating bucket 46 acts to prevent lateral movement of the drilling tool 26. This is particularly important from a safety perspective as the drilling tool 26 is prevented from swinging out of position during loading/unloading. It is envisaged that as the drilling tool lifter 36 moves the drilling tool retaining portion 42 from a first position towards an elevated position, a linear action will move the drilling tool down towards the lower end of the drilling tool lifter 36. By providing the locating bucket 46 at the lower end of the drilling tool retaining portion 42, the drilling tool is intended to slide and be guided into the locating bucket 46. In one form of the present invention, a linear actuator is used to move the drilling tool towards the lower end of the drilling tool lifter 36. Additionally or alternatively, the locating bucket 46 may be linearly actuated to move towards the drilling tool. Alternative drilling tool locating arrangements may be implemented. It is envisaged that any retention means that will secure the drilling tool within the drilling tool retaining portion 42 may be used, for example clamps.

The drilling tool replacement apparatus 10 further comprises a transfer apparatus 48 adapted to transfer drilling tools 26 between the drilling tool holder 32 and the drilling tool lifter 36. As best shown in FIG. 5, the transfer apparatus 48 comprises a grip arm 50 that is moveable between a raised position and a lowered position by a hydraulic cylinder. At the lower end of the grip arm 50 there are provided a grip clamp 52 that is adapted to releasably engage and retain a drilling tool 26.

As best seen in FIG. 5, the grip arm 50 is mounted on a bracket 54. The bracket 54 is suspended on a track 56 that spans the distance between the drilling tool holder 32 and the drilling tool lifter 36. The engagement of the bracket 54 and the track 56 permits the bracket 54 the slide along the length of the track 56 between the drilling tool holder 32 and the drilling tool lifter 36. It is envisaged that the movement of the brackets along the track may be actuated by any linear actuator available in the art, In the embodiment shown in the Figures, a rack and pinion arrangement is used to actuate the movement of the bracket 54 along the track 56.

In use, the bracket 54 can be moved along the track 56 such that the grip arm 50 is positioned above a drilling tool compartment 34 of the drilling tool holder 32. The grip arm 50 extends such that the grip clamp 52 can engage with the drilling tool 26. Once engaged, the grip arm 50 can retract, thereby lifting the drilling tool 26 out of the drilling tool holder 32. As best in seen in FIG. 3, the bracket 54 may slide along the track 56 such that the drilling tool 26 is carried towards the drilling tool lifter 36. Once positioned above the drilling tool retaining portion 42, the grip arm 50 again extends to position the drilling tool 26 in the drilling tool retaining portion 42. The grip clamp 52 disengages the drilling tool 26, retract and be positioned clear of the drilling tool lifter 36. When a drilling tool 26 is being removed from the drill string, the operation is reversed. Whilst the transfer apparatus 48 shown in the figures comprises a single grip arm 50 suspended on a track 56 it is envisaged that other arrangements are possible, including parallel grip arms 50. Any apparatus that is adapted to releasably engage and lift the drilling tools 26 out of the drilling tool holder 32 and deposit them in the drilling tool lifter 36 will be suitable for use.

The transfer apparatus 48 shown in the Figures is particularly useful as the grip arm 50 may be positioned above any of the drilling tool compartments 34 to retrieve drilling tools 26. This allows the selection of particular drilling tools 26 selection depending on the drilling requirements.

Once a drilling tool 26 is loaded into the drilling tool retaining portion 42, the lifting arm 44 can be actuated to lift the upper end 40 of the drilling tool retaining portion 42, thereby moving the drilling tool retaining portion 42 and the drilling tool 26 towards an elevated orientation. As the drilling tool retaining portion 42 is lifted, linear action will move the drilling tool 26 to the lower end 38 of the drilling tool retaining portion 42 and into the locating bucket 46. The drilling tool retaining portion 42 is lifted until it is in aligned with the drill mast 20 and in a position ready to be added to the drill string.

The drilling tool replacement apparatus 10 of the present invention may be used to position a drilling tool 26 beneath a drill rod 30 that is already coupled to the drill rotation source 24. Alternatively, the drilling tool replacement apparatus 10 of the present invention may be used to position a coupled drilling tool 26 and drill rod 30 beneath a drill rotation source 24.

As would be appreciated by person skilled in the art, the first drill rod in the drill string is known as a starter rod 30. The drilling tool 26 is directly coupled to the starter rod 30 and additional drill rods 30 may be coupled to the starter rod 30 as drilling continues. The starter rod 30 is similar to the standard drill rods 30 but it is typically shorter in length than the other drill rods 30 to compensate for the length of the drilling tool 26. In a typical process the starter rod 30 is hoisted towards the drill mast 20 and is coupled to the drill rotation source 24. Once in position, an operation will manually position the drilling tool 26 under the starter rod 30 and couple it to the starter rod 30.

In the embodiment shown in the Figures, the drilling tool lifter 36 has an elongate drilling tool retaining portion 42. The inventors have determined that such a configuration allows for the drilling tool retaining portion 42 to further receive and retain a drill rod and in particular, a starter rod 30. The inventors have found that by positioning both a drilling tool 26 and a starter rod 30 in the drilling tool retaining portion 42, the drilling tool 26 and the starter rod 30 may be coupled in the drilling tool retaining portion 42 prior to being moved to an elevated orientation that is substantially parallel to the drill mast 20 for attachment to the drill rotation source 24.

As discussed above, the starer rod is typically shorter than subsequent drill rods 30 to compensate for the length of the drilling tool 26. As would be appreciated by a person skilled in the art DTHH tools are typically much longer than RD tools. This can lead to different total lengths of drilling tools 26 and starter rods 30. In the preferred embodiment shown in FIG. 7, the length of the RD tool 52 has been increased to match that of the DTHH tool 54. The inventors have found that this will result in constant drilling depth regardless of which drilling tool 26 is required.

The drilling tool 26 and the starter rod 30 are adapted to screw into one another in the substantially horizontal plane on the drilling tool lifter 36 by way of complementary female joints (not shown) and male joints 56. The apparatus 10 further comprises a rod rotator 58 adapted to couple the starter rod 30 to the drilling tool 26. In the embodiment shown in the figures, the rod rotator 58 is mounted on the drilling tool retaining portion 42 of the drilling tool lifter 36. The rod rotator 58 is mounted on the upper end 40 of the drilling tool retaining portion 42 and is adapted to rotate a starter rod 30 mounted in it. To facilitate the coupling, a drilling tool 26 is loaded into the drilling tool retaining portion 42 and is retained in position. The starter rod 30 is mounted into the drilling tool retaining portion 42 and mounted in the rod rotator 58. The actuation of the rod rotator 58 will rotate the starter rod 30 relative to the drilling tool 26, thereby screwing the starter rod 30 into the drilling tool 26, coupling the two together. In a preferred embodiment, the rod rotator 58 comprises one or two rotating rubber/nylon drums (not shown) that a starter rod may rest on. When the drum is rotated, the starter rod 30 is also rotated. As an alternative to drums, the rod rotator could comprise a clamping arrangement that includes an actuation mechanism to rotate one portion relative to the other.

Once the drilling tool 26 and the starter rod 30 are coupled, the lifting arm 44 can be actuated to lift the upper end 40 of the drilling tool retaining portion 42, thereby moving the drilling tool retaining portion 42, along with the coupled drilling tool 26 and starter rod 30 towards an elevated position. As the drilling tool retaining portion 42 is lifted, a linear action will similarly force the drilling tool 26 to the lower end 38 of the drilling tool retaining portion 42 and into the locating bucket 46. The drilling tool retaining portion 42 is lifted until it is in aligned with the drill mast 20 and in a position ready to be added to the drill string.

The inventors have found that it is particularly advantageous to provide the drill rotation source 24 on the outside of the drill mast 20. As best seen in FIG. 1, having the drill rotation source 24 on the outside of the drill mast 20 allows the drilling tool retaining portion 42 to position the drilling tool 26 and starter rod 30 directly under the drill rotation source 24. Once in position, the drill rotation source 24 can be engaged with the starter rod 30. It is envisaged that the drill rotation source 24 may then be lifted upwards to lift the starter rod 30, thereby lifting the drilling tool out of the locating bucket 46. Once lifted clear of the locating bucket 46, it is envisaged that the drilling tool retaining portion 42 can be lowered and the drilling tool can be positioned for drilling operation. In the embodiment shown in the figures, the drill mast is solid 20. Unlike convention lattice masts, the inventors have found that solid mast allows for the overall cross section of the drill mast 20 to be reduced, whilst maintaining structural integrity. This has been found by the inventors to provide additional space on the drilling platform.

The inventors have determined that by using a drilling tool replacement apparatus 10 that can position a drilling tool 26 for attachment to a drill string is particularly advantageous as is reduces the manual operation required to couple/decouple the drilling tool 26 to the drill string. Furthermore, in the embodiment of the present invention where the drilling tool 26 is coupled to a starter rod 30, it is envisaged that the starter rod 30 and the drilling tool 26 may be positioned beneath and coupled to the drill rotation source 24 without any physical human interaction. The inventors understand that this configuration not only minimises risk to operators but may also permit the faster removal and replacement of drilling tools 26.

It is further envisaged that the drilling tool replacement apparatus 10 may be used in combination with apparatus adapted to load drill rods 30 onto a drill string. Such apparatus include the drill rod handling apparatus as described in the Applicants co-pending provisional application AU2018900521. It is envisaged that certain components of the drill rod handling apparatus may be used to in combination with, or as replacements for the above described features. In particular, the applicant envisaged the rod lifter of AU2018900521 to be suited for use as the drilling tool lifter 36 of the present invention.

Despite the similarities, the rod retaining portion of the rod lifter of AU2018900521 is not designed to receive drilling tools 26, particularly when the rod locating pin 60 is included. In order to facilitate the use of a the rod lifter of AU2018900521 for the handling of drilling tools 26, the drilling tool replacement apparatus 10 further comprises a rod pin adapter 62 that engage with the rod locating pin 60 to provide the locating bucket 46 at the lower end of the drilling tool retaining portion 42. As best seen in FIG. 6, the rod pin adapter 62 comprises a centrally located female receptacle 64 that is adapted to fit over a rod locating pin 60. The rod pin adapter 62 further comprises a bucket portion 66 that is suitable for use as the locating bucket 46 of the drilling tool lifter 36. In use, the female receptacle 64 of rod pin adapter 62 is intended to slide onto the rod locating pin 60, thereby enabling the use of the bucket portion 66 as the locating bucket 46. The rod pin adapter 62 is retained in position by a clamping means (not shown) It is envisaged that the rod pin adapter 62 may be stored in the drilling tool holder 32 when not in use. Furthermore, the transfer apparatus 48 may be used to transfer the rod pin adapter 62 between the drilling tool holder 32 and the rod retaining portion.

Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. The invention includes all such variation and modifications. The invention also includes all of the steps, features, formulations and compounds referred to or indicated in the specification, individually or collectively and any and all combinations or any two or more of the steps or features. 

1. A drilling tool replacement apparatus, the apparatus comprising: a drilling tool holder adapted to receive one or more drilling tools; a drilling tool lifter adapted to move a drilling tool between a first position and an elevated orientation; and a transfer apparatus adapted to transfer a drilling tool from the drilling tool holder to the drilling tool lifter.
 2. An apparatus according to claim 1, wherein the drilling tool handling apparatus is mounted to a drill platform of a mobile drill unit.
 3. An apparatus according to claim 1, wherein the first position is substantially horizontal to the drilling platform.
 4. An apparatus according to claim 1, wherein the elevated position is substantially parallel to the drill mast.
 5. An apparatus according to claim 1, wherein the one or more drilling tools are received substantially horizontally in the drilling tool holder.
 6. An apparatus according to claim 1, wherein the drilling tool holder is provided with one of more drilling tool compartments.
 7. An apparatus according to claim 1, wherein the drilling tool lifter comprises a drilling tool retaining portion adapted to receive a drilling tool.
 8. An apparatus according to claim 1, wherein the drilling tool lifter comprises a lifting arm coupled to the drilling tool retaining portion.
 9. An apparatus according to claim 8, wherein the lifting arm is adapted to move the drilling tool retaining portion between a horizontal position and an elevated orientation.
 10. An apparatus according to claim 1, wherein the drilling tool retaining portion has a lower end and an upper end.
 11. An apparatus according to claim 10, wherein the lower end is hingedly engaged with the drill platform.
 12. An apparatus according to claim 1, wherein the drilling tool lifter further comprises a locating arrangement.
 13. An apparatus according to claim 1, wherein the locating arrangement comprises a locating bucket adapted to receive and retain a drilling tool.
 14. An apparatus according to claim 1, wherein the drilling tool lifter is adapted to further receive a drill rod.
 15. An apparatus according to claim 14, wherein the drilling tool retaining portion is adapted to receive the drill rod.
 16. An apparatus according to claim 15, wherein the drilling tool retaining portion receives and positions the drill rod directly behind the drilling tool.
 17. An apparatus according claim 14, wherein the drilling tool lifter further comprises one or more rod rotators adapted to facilitate the coupling/decoupling of a drill rod to a drilling tool.
 18. An apparatus according to claim 1, wherein the transfer apparatus is adapted to releasably engage with a drilling tool.
 19. An apparatus according to claim 1, wherein the transfer apparatus is adapted to lift a drilling tool out of the drilling tool holder.
 20. An apparatus according to claim 1, wherein the transfer apparatus is provided with one or more engagement means adapted to couple with the drilling tool.
 21. An apparatus according to claim 1, wherein two or more drilling tool compartments are provided in the drilling tool holder and the drilling tool lifter may engage with drilling tools in either compartment.
 22. An apparatus according to claim 1, the apparatus being adapted to remove a drilling tool from a drill string and replace it with another drilling tool.
 23. An apparatus according to claim 22, wherein the replacement of the drilling tool by the drilling tool replacement apparatus is fully automatic.
 24. An apparatus according to claim 22, wherein the replacement of the drilling tool by the drilling tool replacement apparatus can be completed autonomously.
 25. A method of drilling, the method comprises operation of a drilling unit having a drilling tool replacement apparatus as described above mounted thereon for the addition and/or removal of drilling tools.
 26. A method of replacing a drilling tool, the method comprises the use of a drilling tool replacement apparatus as described above to replace the drilling tool. 